Preliminary analysis of Brazilian Amazonian plant extracts using bench-top assays in a through-put basis aiming the identification of potential antioxidant natural product

Abstract

Plants are a source of compounds that are used for the treatment of human and veterinary diseases. Brazil is one of the richest countries in the world in terms of biodiversity. The present study evaluated extracts using thin-layer chromatography to identify antioxidant activity and determine the presence of groups of compounds, in a large-scale basis. A total of 1,260 aqueous and organic extracts were obtained from plants that were collected in the Amazon and Atlantic rain forests. Thin-layer chromatography was performed to evaluate the presence of alkaloids, anthraquinones, cardioactive glicosides, terpenes, and phenolics and determine antioxidant and radical scavenging activity using the following reagents: Dragendorff’s reagent, KOH, Kedde’s reagent, sulphuric acid, NP reagent, β-carotene, and 2,2-diphenyl-1-picrylhydrazyl (DPPH). Of the 1,260 extracts, 837 (66.43%) presented a β-carotene/bleaching response, and 1,205 (95.63%) presented a radical scavenging response. Alkaloids were found in 203 extracts (16.11%). Anthraquinones were found in 14 extracts (1.11%), cardenolides were found in eight extracts (0.63%). The present findings shows the importance of the Brazilian Amazon plants as sources of antioxidant and radical scavenging active compounds.